03whitegsr

iTrader: (8)

The mixed flow turbine is only on the 7163.

As Geoff mentions in the video, this technology has been used in diesel engines recently. Garrett I think uses it in the Ford Dual Boost turbo and recently released info on axial flow turbines for gasoline applications.

http://turbo.honeywell.com/our-techn...turbochargers/

Read the technical paper on that link to see some of the benefits of the axial flow turbine as well as the dual boost concept.

The future is bright for turbo chargers in OEM applications with downsized GDI engines. Not sure how much will bleed over to the aftermarket though.

I'm curious to know if the housing is actually different for the mixed flow wheel. From what I've found in some SAE papers, the turbine housing is quite a bit different in the ideal mixed flow turbine side.

I'll take an IRL version divided T4 7163 please... Hold the BOV, internal gate and massive (in length) housings and give me a tight package I can fit anywhere.

mrfred

iTrader: (50)

The turbine housing is different for the MFT. I believe that in the video Geoff mentions that the flow from the volutes is vectored to be a cone shape making part axial and part radial flow.

EDIT: You probably already found it, but here is an article on mixed flow turbines:

http://www.hindawi.com/journals/ijrm/2012/589720/

There is another article I read last week, but I can't find it.

Talonboost

Jeepers that's a really good article. Good thing they put figure 2 in there though, or I would not have had a clue how to picture this thing.

I guess the way I picture it now, the whole turbine wheel is kind of a curved axial flow arrangement.
Whereas on a "regular" turbine wheel, the inducer tips act kind of like a tangential impulse turbine, and it is only the exducer that is like an axial flow thing.

RWD4G63

The 7163 prototype outspool'd a 6758 when Perrin was testing it on their Subaru. If the production model has even more performance, this turbo will revolutionize the 500whp turbo market.

FastGti69

It's good for spool yes. The torque spike on that **** will kill trannys and blow motors. That's the problem, though. Happened a lot on the cobalt SS when people threw on the 6758, imagine the 7163... LOL

mrfred

iTrader: (50)

Boost control can keep the torque at reasonable levels, but I suppose that insanely fast transient response could also be a concern. I don't think that would bother an Evo owner though.

RWD4G63

Eh, I think if you put some 1/2 studs in the block you could keep the head down, you'd just have to have a tuner who knows what they're doing.

Transmissions...yeah that's always an issue. I'm glad I don't have to deal with that haha.

FastGti69

Yea, I had a boost ramp on the 6758 in my car. It was too much torque insanely fast. I think that's what ultimately led it to blow. I hope these new EFRs don't blow as much.

Tuning is main part, most others withthe 6758 in the SS scene were blowing the trans left and right. Just stripping the syncrose because their tuner didn't ramp the boost. Huge spikes would kill it. Most of the evo's these days are pretty much built now so what am I saying haha.

03whitegsr

iTrader: (8)

Great journal article. While I don't have a Garrett equivalent article, I would bet they came to the same conclusions on the TiAl turbine wheels. Just based on a post I read from a Garrett guy that is on here anyway. Although, it is worth considering the TiAl wheel only lost out because of an assumed 5% reduction in thermal efficiency due to a compromised blade design to make it more robust to deal with FO impacts. There might be some flex room in there to make the TiAl slightly less robust without taking such a big hit on thermal efficiency. Even then though, it seems like you are just compromising reliability for minor gains that could easily be lost with simply an improper turbine to compressor wheel match up.

To me, this is what FP has done. They simply tried to hone in on a best possible match between turbine and compressor wheel when matched up with "typical" 4G63 VE and boost requirements. Pick a turbine wheel and housing that matches the desired HP and boost response goals, then build a compressor wheel and housing package to match. Its funny how much emphasis is put on the compressor wheel when it's the turbine wheel that determines 90% of the turbos character and power potential.

RWD4G63

If you've noticed, after their start-up problems, these turbos have been extremely reliable. And Borg knows a thing or two about turbine/compressor match . They're better at it than Garrett IMO.

I'm confused. Are you talking about bolt on turbos? The FP black is a terrible compressor/turbine match IMO, and it is limited by how big of a turbine you can fit in a bolt-on housing. Garrett's bolt-on versions of their turbos never really panned out due to turbine housing sizing.

I would say the turbine determining 90% of both character and power potential is an overstatement. A TD06SL2 turbine paired with a 16G compressor and it with a 3076R compressor will have quite different response and power characteristics. Maybe 60-70% of each would be a more realistic figure.

mrfred

iTrader: (50)

Where did you read the BW is giving up 5% in thermal efficiency in order to be able to use a TiAl turbine wheel? And I'm not sure what you mean by thermal efficiency.

03whitegsr

iTrader: (8)

Are the EFRs proving reliable? There are only a very few evos running them. What communities are pushing the EFR turbos hard at this point?

As for better matching, Garrett engineers recommend a select number of combinations as they are properly matched. Unfortunately the marketing team seems to have put out a bunch of junkers to fill the gaps they think existed. I do see your point though and you can definitely end up with a Garrett turd if you don't know your turbos. BW is no different though, they have a whole line of non-EFR turbos where 50% of them are turds.

Same thing here. Handful that I feel are well optimized and other compromised ones mixed in. The HTA green and HTA3582 for example are excellent performers. Read the posts on here about them and it is clear FP was optimizing for overall performance. You are right on the black, it's all about stuffing as much compressor in as possible.

Fair enough. I was talking about when you have a reasonable compressor in there but if you want to go to extremes, yes my theory falls apart. Take a power and target and IMO, you start at the turbine wheel and housing first then select a compressor to match. The norm seems to be select a compressor wheel and adjust the turbine until it works though and I think this is a backwards approach.

That article shows data with an assumed 5% penalty on efficiency for the TiAl turbine wheel. I say thermal efficiency but in reality it is mechanical efficiency. Regardless, that article assumes the TiAL turbine is 5% less efficient on converting hot gas into mechanical energy to drive the compressor.

mrfred

iTrader: (50)

Which article?

03whitegsr

iTrader: (8)

The one you posted.

Read the paragraphs surrounding figure 20 if you don't know what I'm referring to.

mrfred

iTrader: (50)

Just wanted to be sure that we are on the same page. That paper was written by people at IHI, so the BW folks might differ in opinion on whether the use of gamma-TiAl necessitates a turbine wheel efficiency penalty to make the wheel sufficiently robust.

Getting back to MFT design for a second, one interesting aspect of that paper is an obvious difference in wheel shape (Figure 2) where the MFT appears more suited to make better use of axial flow, while this picture from FR comparing an EFR MFT to an EFR RFT shows no obvious difference in fin design apart from the extended tips on the MFT.